Wastewater treatment works change the intestinal microbiomes of insectivorous bats

Abstract

Mammals, born with a near-sterile intestinal tract, are inoculated with their mothers’ microbiome during birth. Thereafter, extrinsic and intrinsic factors shape their intestinal microbe assemblage. Wastewater treatment works (WWTW), sites synonymous with pollutants and pathogens, receive influent from domestic, agricultural and industrial sources. The high nutrient content of wastewater supports abundant populations of chironomid midges (Diptera), which transfer these toxicants and potential pathogens to their predators, such as the banana bat Neoromicia nana (Vespertilionidae), thereby influencing their intestinal microbial assemblages. We used next generation sequencing and 16S rRNA gene profiling to identify and compare intestinal bacteria of N. nana at two reference sites and two WWTW sites. We describe the shared intestinal microbiome of the insectivorous bat, N. nana, consisting of seven phyla and eleven classes. Further, multivariate analyses revealed that location was the most significant driver (sex, body size and condition were not significant) of intestinal microbiome diversity. Bats at WWTW sites exhibited greater intestinal microbiota diversity than those at reference sites, likely due to wastewater exposure, stress and/or altered diet. Changes in their intestinal microbiota assemblages may allow these bats to cope with concomitant stressors.

Characterization of the bacterial microbiome of non-hematophagous bats and associated ectoparasites from Brazil

“…Lutz et al ( 2019) also found a high relative abundance of Gammaproteobacteria in the oral and distal gut microbiome of insectivore and frugivore bats from Uganda and Kenya. Our findings were also similar to those found in previous studies performed in Mexico (Carrillo-Araujo et al, 2015), France (Hughes et al, 2018), southeastern Brazil (Cláudio et al, 2018), China (Xiao et al, 2019), and South Africa (Mehl et al, 2021), which have also found a high relative abundance of Proteobacteria in the gut microbiome of bats. Indeed, chiropterans have a higher proportion of Proteobacteria in The reason for this difference is likely to be linked to the bat adaptation to flight and their rapid intestinal transit (Hughes et al, 2018;Nishida and Ochman, 2018;Jones et al, 2022).…”

“…Many authors report a high abundance of Proteobacteria in bat gut flora. In South Africa, Mehl et al (2021) analyzed the composition of intestinal bacteria of insectivorous bats ( Neronomica nana ) sampled on wastewater treatment work and reference sites. The authors reported Proteobacteria abundance (range of 19.9 to 46.6%) comprising four different classes (Alphaproteobacteria, Betaproteobacteria, Epsilonproteobacteria and Gammaproteobacteria).…”

“…The authors reported Proteobacteria abundance (range of 19.9 to 46.6%) comprising four different classes (Alphaproteobacteria, Betaproteobacteria, Epsilonproteobacteria and Gammaproteobacteria). Additionally, the authors reported that the bat sampling site was the most influential parameter on microbiome constitution and diversity ( Mehl et al, 2021 ).…”

Effects of anthropogenic stress on hosts and their microbiomes: Treated wastewater alters performance and gut microbiome of a key detritivore (Asellus aquaticus)

“…Tamminen et al, 2021 ), but not host‐associated microbiomes (but e.g. Mehl et al, 2021 ). Our data provide rare insight into differential effects of wastewater and dissolved chemicals on host‐associated microbiomes.…”

“…Desiante et al, 2022 ), and, thereby, potentially influence environmentally acquired microbiomes of the host (e.g. Mehl et al, 2021 ).…”